Evaporator



Sept. 14 1926;

H. FOTHERGILL EVAPORATOR Filed August 2, 1924 2 Sheets-Sheet l /M/E/vro:

HAZ@ FOTH 5260.1. YIMLMMMMJJM Sept. 14,1926. f 1,600,106

H. FOTHERGILL EVAPORATOR Filed August 2, 1924 2 sheetsheet 2 EQ' rg'.

I lllv HARRY FOTHEQILL hf ifm@ mdmmnwf/qly' Patented Sept.l 14, A1926. i,

UNITED STATES 1,000,100 PATENT oFFflcafi,

HARRY FOTHEBGILL, OF WESTMINSTER, LONDON, ENGLAND.

EVAPORATOR.

.Application filed August 2, 1924, Serial 110.729,788, and in Great Britain August 24, 1923. v

lThis invention relates to evaporators of the kind in which/the liquid to be evaporated is first heated and afterwards introduced into a chamber of lower pressure 1n i which a portion of the liquid flashes into vapour, the liquid being maintained 1n continuous circulation through the heater and flashing chamber by means of a pump, as for example in the manner described- 1n l the specification of my prior appllcation The object of the present'invention is to provide improvements in evaporators ofthe kind referred'to.'

i -In accordance with the principal feature of the present invention the flash or evaporating chamber is arranged around the heater so that the apparatus is in the form of a self-contained unit. From the lower l part of the evaporating chamber the liquid which is not evaporated is withdrawn by a pump and delivered through the heater again in continuous circulation, additional make-up liquid being admitted into the sysi tem as and when required, and for the purpose of preventing the liquid increasing in density a portion of the liquid in continuous circulation may be discharged from the apparatus on the delivery side of the pump,

1 thus avoiding undue concentration of the li uid.

qwhen operating with li uids containing scale-forming matter, the eating surfaces in the heater are liable to become covered 0- by a deposit, and under such conditions would require cleaning periodically. For this purpose in accordance with the present invention the heating elements maybe so arranged that they can be quickly removed I `from the apparatus, and if desired a spare set of elements introduced into the evaporator so that the rocess of evaporation may be continued wit out stoppage of the lant except during the short time when the eati i element 1s bein changed. ith the object o obtaining a high'sp'eed of liquid through the tubes of the heater and thereby reventing the formation of scale in the tu the heater may be divided into a number of passes so that the liquid passes through groups of tubes in series, the ast grou discharving into the pipe or assage lea to Athe eva rating chamber.

The heater 'quid is pre erably introduced' thi'ughm i into the evaporating 'chamber nozzles which may in accordance with the invention maintain ahead onthe discharge side of the heater and thus prevent any flashing or boiling of the liquld before-it enters the eva orating chamber. The liquid system may e so designed that the head produced will require a pressure at the pump discharge in excess of atmospheric pressure although the pressure in the evaporating chamber may be' below atmo' here, thus permittin of the continuous disc arge of concentrate liquid without the use of a special extracting device. These' nozzles so have the advantage of producing bursting jets Vof liquid which materially assist in breaking up the liquid and promoting eiiicient evaporation Without priming.

The steam required forheating purposes may be supplied from any convenient source and the apparatus may work under an desired pressure depending on theconditons and requirements of the plant; Fo\ example, steam for the heater may be bled g from a low pressure section of a steam turbine and the 'evaporator' chamber maintained under vacuum by connection to the main condenser of some other condenser'or distiller under vacuum. J High ressure steam may be led direct into the eater for raising the temperature-` of the liquid, but with the object of avoid ing a high temperature in the heater and the baking of) scale on the tubes, I prefer to use such high pressure steam in one or more ejector nozzles designed to extract vapour produced in the evaporator and com press such vapour into the heater. Two or more of these ejector nozzles or compressors may be arranged in series, and by using a portion of the vapour from the eva orator in this manner the quantity of hig pressure steam required is reduced and the efficiency of the plant is thereby consider-A abl increased.

e accompanying drawings, 1, 3, 100

4 and 5, show in sectional elevation convenient forms of apparatus constructed in. accordance with the present invention, the same letters of reference being used to denote similar parts in the various drawings. 41015 Fig. '2 is a sectional plan view on the line A-A in Fi 1, and Fig. 6 is a cross sec tion on Athe hne B`-B in Fig. 5.

`In each example the heater consists of a number-of straighttubes a arranged within; 110

the casin b having an inlet pipe c for the supply 0 heating steam, and an outlet pipe al for the discharge of the drama e water. Arranged around the casin b of t e heater is an outer vessel e which orms the evaporating chamber which is essentially at a lower pressure than that corresponding to the temperature of the li uid discharged into it from the heater, and om this chamber the li uid to be evaporated is withdrawn through t e pipe f by the pump g and d1scharged through the tubes of the heater back again into the evaporating chamber through the nozzles h. The steam liberated from the liquid on'leaving the nozzles passes away from the evaporator through the plpe p which may be connected to a condenser.

In Figs. l and 2 the heater is vertically disposed, the evaporating chamber belng concentricall arranged around the upper portion of t e heater, the arrangement being such that the heated liquid on leavingl the top of the heater is introduced into the top'of the evaporating chamber through the nozzles 71,. Additional make-up liquid is admitted through the pipe m into the vessel e forming the evaporating chamber by means ofl an automatic float control Z which maintains thefliquid level therein, and a portion of the liquid in continuous 'circulation is discharged through the pipe n, for the purpose hereinbefore described. 4

In Fig. 3, which is a modification of Fig. 1, high pressure steam is utilized for raising the temperature of the liquid rpassing through the heater, and with the object of avoiding a high temperature of steam in the heater, the high pressure steam supply o is connected to the nozzle s of the ejector t which is designed to withdraw from the pipe p a portion of the vapour produced in the evaporator and compress such vapour into the heater through the pipe c in a known manner. Additional steam, such as exhaust steam from auxiliary machinery, may be admitted through the pipe 7'. The liquid headers and y of the heater, are divided into compartments so arranged that the liquid passes through groups of tubes in series.

In Fig. 4 the lower liquid header y is connected to the heating tubes only bywhich it is suspended in the steam space of the casing b, the upper header being provided with the necessary inlet and outlet assages and secured, as by bolts, to the ody of the evaporator. With such an arran ement it will be readily understood that by isconnecting the upper header from the body, of the evaporator the water headers and heating elements may be quickly removed and a clean set of heatin together with their water headers introduced into the evaporator. The heated water is delivered'from the heater through the pipe elements v into an annular passage fw surrounding the vessel e, and from this passage the water is introduced into the evaporating chamber through a ring of circumferentially disposed nozzles It which are preferably arranged to spray the water in a peripheral ilm over the inside surface of the vessel e. A baiile u is provided to prevent water bef ing sprayed into the steam space in the upper part of the vessel e and further bailles j and lc are arranged in the lower part of the heater to collect the deposits which can be periodically removed by taking. of the cover z.

Figs. 5 and 6 show an evaporator in accordance with my invention in which the heater is placed horizontally, the arrangement of the headers and tubes being similar to that shown'in Fig. 4 so that they may be withdrawn from one end of the casing b for cleaning purposes when required. The

heated waterfrom'l the header is delivered butthis does not necessarily mean that it isv under vacuum. If the pressure and corre- Isponding temperature in the heater are high enough the evaporating chamber may be maintained at atmospheric or even higher p pressure.

What I claim and desire to secure by Letters Patent is l. Apparatus f for evaporating liquids, comprising a vessel infwhich the liquid to be evaporated is heated, an evaporating chamber through which said heater passes,

Vand a pump for circulating liquid from the lower part of said evaporating chamber and through said heater and again into said evaporating chamber.

2. Apparatus .for levaporating liquids comprising a .vessel in which the liquid to be evaporated is heated, an evaporating chamber, said heater passing through said evaporating chamber, and apump for circulating liquid through said heater and into said evaporating chamber. f

3. Apparatus for evaporating' liquids comprising a vessel constituted by tubular surfaces connected .to headers in which the liquid to be evaporated is heated, an evaporating chamber, said heater passing through said evaporating chamber, and a pump for circulating liquid from the evaporating chamber through said tubular surface heater and back into said evaporating chamber.

evaporating chamber, circumferentially dis-pv posed spraying nozzles adapted to spray sideways so as to project a peripheral iilm tinto the evaporating chamber, and a pump for circulating liquid through said heater and thence to said spraying nozzles and into said evaporating chamber.

6. Apparatus for evaporating liquids comprising a heater consisting of tubes arranged between headers, an evaporating chamber through which said tubes pass discharge nozzles .leading from the heater to the evaporating chamber, and aA pump for circulating the collected liquid from the 'evaporating chamber through the heater and thence through the nozzles again into the evaporating chamber.

7. Apparatus for evaporating ,liquids comprising an evaporating chamber-having an internal circular chamber, a heater located in said circular chamber so as to pass through said evaporating chamber, means for maintaining in the evaporating chamber a pressure lower than that corresponding to the temperature of the liquid in fthe heater, and a pump for circulating the li uid` from the evaporating chamber throug the heater and discharging it again into the evaporating chamber.

8. Apparatus for evaporating liquids comprising a vessel in which the liquid to be evaporated is heated, an evaporating chamber, said heater passing through said evaporating chamber and a pump having its suction side kconnected to the lower end of the evaporating chamber and its delivery side adapted to deliver both to the heater and the evaporating chamber.

9. Apparatus for evaporating liquids comprising a vessel constituted by tubular surfaces connected to headers in which the liquid to be evaporated is heated, an evaporating chamber through whichv said heater passes, a pump for circulating liquid through said tubular surface heater and evaporating chamber, a connection from the suction side of the pump to thelower part of the evaporating chamber beneath the level of the liquid collected therein and a connection from the delivery side of the pump to a header and to nozzles 'projecting into'the evaporating chamber. v

l0. Apparatus for evaporating liquids comprising an evaporating chambei` having an internal circular chamber, a heater located in said circular chamber so, as to pass through said evaporating chamber and adapted to be removed in one piece from said circular chamber, means for maintaining in the evaporating chamber a pressure lower than that corresponding to the temperature of the liquid in the heater, and a pump for circulating the liquid through the heater, and discharging it into the evaporating chamber.

l1. Apparatus for evaporating liquids comprising a vessel in which the liquid to be evaporated is heated, an evaporating chamber, spraying nozzles adapted to spray heated liquid from the heating` vessel into the evaporating chamber, a baiile for preventing the spray from said nozzle entering the steam space of the evaporating chamber, and a pump or circulating vliquid through said heater and thenceto said spraying nozzles and into said evaporating chamber. f

12. Apparatus for evaporating -l`liquids comprising a cylindrical vessel having its axis vertically disposed, a liquid header arranged at each end of said vessel and connected. together by vertical tubes through which the liquid to be heated is circulated by means of a pump, and an evaporating chamber through which the heating vessel passes and into which the heated liquid is delivered.

`13. Apparatus for evaporating liquids comprising a vessel in which the liquid to be evaporated is heated, an evaporating chamber through which ,the heater passes, spraying nozzles adapted to spray heated liquid from the heating vessel into the evaporating chamber, bailes in the lower part of the evaporating chamber serving to collect deposits from the liquid, and a pump for circulating liquid through said heater and thence to said spraying nozzles and into said evaporating chamber. 14. Apparatus for eva orating liquids comprising a vessel in which the liquid to be evaporated is heated, an evaporating chamber through which the heater passes, spraying nozzles adaptedto spray heated liquid vfrom lthe heating vessel into the evaporating chamber, a baiiie for preventing the spray from said nozzles entering the steam space of the evaporating chamber, bales in the lower lpart of the evaporating chamber serving to collect the deposits from the liquid, and a pump for circulating liquid through said heater and thence lto sald spraying nozzles and into said evaporating chamber.

15. Apparatus for e'vaporating liquids comprising an evaporating chamber into which heated liquid is introduced, a heater vessel in which the liquid is heated said heater vessel passing through said evaporating chamber, a circulating pump having its suction pipe connected to the lower end of the evaporating chamber beneath the level ot' the liquid collected therein, the liquid discharged by said pump passing through said heating vessel and thence into the evaporating chamber above the level of the liquid collected therein.

16. Apparatus for evaporating liquids comprising a vessel in which the liquid to be evaporated 'is heated, an evaporating chamber through which said heater passes, a pump for circulating the liquid through said l1eater,and discharging it into the evaporating chamber, an outlet on the discharge side ot the pump between said pump and said heater and means for producing a head upon the pump such as will require a pressure on the pump discharge in excess ot' atmospheric pressure whereby the continuous discharge ot' concentrated liquid is permitted without the use of any special extraction device.

17.`Apparatus for evaporating liquids comprising a vessel in which the liquid to be evaporated is heated, an evaporating livery side of the pump for the discharge' of concentrated liquid against atmospheric pressure.

18. Apparatus for evaporating liquids comprising a heater, an evaporating chamber to which the heated liquid is delivered, a pump for circulating the liquid through the heater and to the evaporating chamber, nozzles to which the heated liquid is delivered by the circulating pump said nozzles being so designed as to olfer such resistance to the fiow of liquid through them that the pressure in the discharge side of the circulating pump is maintained above atmospheric pressure and a discharge pipe connection for concentrated liquid leading from the discharge side of pump through which concentrated liquid is delivered against atmospheric pressure.

In testimony whereof, I aix my signature HARRY FoTHERGILL. 

